In the prior art, a steering device having a means for detecting whether or not a driver grips a steering wheel is discussed in Japanese Laid-open Patent Publication No. 2008-059459, PCT international application No. 2003-535757, and Japanese Laid-open Patent Publication No. 2015-147531.
In Japanese Laid-open Patent Publication No. 2008-059459, a steering device is discussed, in which a grip detection means for detecting whether or not an operator grips a steering wheel is arranged along a circumference of the steering wheel, and an alarming means is selectively operated depending on a result of the detection from the grip detection means.
In PCT international application No. 2003-535757, a vehicle steering wheel provided with a plurality of sensors is discussed, in which each of the sensors is divided into a plurality of segments to detect a position of a driver's hand on the steering wheel.
In Japanese Laid-open Patent Publication No. 2015-147531, a steering device having a structure simplified by reducing the number of wires is discussed. This steering device has an electrostatic capacitive sensor installed in a steering core. This electrostatic capacitive sensor has a flexible plate having flexibility and a plurality of electrostatic capacitance detection sensors provided on the flexible plate. While each electrostatic capacitance detection sensor is installed in the steering core, they are arranged at predetermined intervals along a circumferential direction of the steering core by using a wheel extending direction as an axial core and are formed to extend along the wheel extending direction, respectively. While a plurality of electrostatic capacitance detection sensors are installed in the steering core, they are grouped such that electrodes neighboring in the circumferential direction of the steering core belong to different groups.